python-100-days/day8_caesar_cipher.py at main · IlonaNe/python-100-days · GitHub

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alphabet = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
            'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
direction = input("Type 'encode' to encrypt, type 'decode' to decrypt:\n")
text = input("Type your message:\n").upper()
shift = int(input("Type the shift number:\n"))


def caesar(original_text, shift_amount, cipher_direction):
    cipher_text = ""
    if cipher_direction == "decode":
        shift_amount *= -1

    for letter in original_text:
        if letter not in alphabet:
            cipher_text += letter
        else:
            shifted_position = alphabet.index(letter) + shift_amount
            shifted_position = shifted_position % len(alphabet)
            cipher_text += alphabet[shifted_position]

    print(f"The {cipher_direction}d text is {cipher_text}")
caesar(original_text=text, shift_amount=shift, cipher_direction=direction)

# def encrypt(original_text, shift_amount):
#     cipher_text = ""

#     for letter in original_text:
#         shifted_position = alphabet.index(letter) + shift_amount
#         shifted_position = shifted_position % len(alphabet)
#         cipher_text += alphabet[shifted_position]

#     print(f"new index {shifted_position} and it is a letter {cipher_text}")
# encrypt(original_text=text, shift_amount=shift)

# def decrypt(original_text, shift_amount):
#     cipher_text = ""

#     for letter in original_text:
#         shifted_position = alphabet.index(letter) - shift_amount
#         shifted_position = shifted_position % len(alphabet)
#         cipher_text += alphabet[shifted_position]

#     print(f"new index {shifted_position} and it is a letter {cipher_text}")
# encrypt(original_text=text, shift_amount=shift)

should_continue = True

while should_continue:
    caesar(original_text=text, shift_amount=shift, cipher_direction=direction)
    result = input("Type 'yes' if you want to go again. Otherwise type 'no'.\n")
    if result == "no":
        should_continue = False